Fluid distributing plate



Nov. l5, 1949 H. RODMAN FLUID DSTRIBUTING PLATE Filed Oct. 31, 1945atented Nov. 15, 1949 2,491,984 FLUID DISTRIBUTING PLATE Hugh Rodman,

Oil Products Company,

tion of Delaware Chicago, Ill., assigner to Universal Chicago, Ill., acorpora- Application October 31, 1945, Serial No. 625,851

Claims.- (Cl. 23-288) This invention relates to an improved type of flowdistribution plate, or more specifically to an improved form ofperforated distribution grid which will operate to reduce the velocityof a charge stream flowing therethrough, as well as distribute the uidstream uniformly across the diameter of the vessel being charged.

Various well known hydrocarbon conversion processes such as catalyticcracking, catalytic dehydrogenation, catalytic aromatization, etc., makeuse of finely divided solid particles to catalytically promoteconversion reactions. In fluid processes of this type, the conversionofthe fluid reactants and the regeneration of the contaminated catalystparticles is accomplished continuously in separately confined reactionand regenerating vessels between and through which catalyst iscontinuously passed in series. The mass of catalyst undergoingregeneration in the regenerating vessel is maintained in the fprm of afluid-like bed of subdivided solid catalyst particles. Fluidization ofthe bed is accomplished by passing the oxidizing gas employed to burncombustible contaminants from the catalyst and the resulting hotcombustion gases upwardly through the bed at a velocity which partiallycounteracts the force of gravity on the catalyst particles and causeshindered settling of the latter. A mass of catalyst being employed topromote the conversion reaction in the 'reaction vessel may also bemaintained in a similar fluidlike conditionby passing the uid reactantsand the resulting fluid conversion products upwardly through the bed ata velocity controlled to keep the latter in a relatively densefluid-like condition. A perforated distribution plate is normallyemployed at the lower end of each of the vessels to obtain uniformdistribution of the charge streams to each of the beds to be maintainedin a uidized condition.

It is an object of this invention to provide an improved form ofperforated grid plate which effects uniform distribution and diffusionof a fluidized charge stream while permitting greater use of the lowerportion of a contacting chamber.

Another object of the invention is to provide an improved form of gridwhich reduces the velocity and the kinetic energy of a uid stream andentrained solid particles which may be carried by the iiow stream.

A further object of the invention is to provide algrid plate whichprevents transverse movement or recirculation of fluid material 'andentrained solid particles at the inlet face of the grid plate. Atpresent, in commercial iiuidcatalyst couver- Vreacl'ling a hole in ordersion units, of the type mentioned above, both the' reactor andregeneration vessels normally have a perforated grid plate to distributethe respective incoming fluidized stream across the area of the vesseland this plate is usually placed at the tanv the lower inlet cone andthe cylindrical body of the chamber itself. However, it has been foundthat with the present distribution plates, having straight-throughperforated holes at spaced points on the plate, the fluid stream andcatalyst particles pass through the grid at teo great a v tioned at apoint just above the 'inlet conduit. Also, that a portion of thecatalyst particles being carried in the gas stream impinge against theflat bottom of the plate and travel horizontally until gent line betweenthe grid plate. In addition, it hasbeen found that a considerableportion of the catalyst particles fall back against the bottom inletcone of the vessel and must be recirculated by the iiuid stream enteringthe inlet conduit such that anv the grid plate.

With the present types of grid plate, a tapered undesirable conditionresults under inlet cone for the chamber, is of course necessary, toreduce the velocity of the placing of the grid plate across the junctionof the cone and the cylindrical portion of the chamber serves todistribute the charge stream across the full area of the chamber. Theimproved form of distribution plate comprising this'inventionV has aninlet surface or up'- stream side which comprises a plurality of closelypositioned and tapered inlets each of which lead to a small sloping ordiagonally placed hole that passes through the plate to the outlet side.The small holes are arranged in groups of three and sloped so that eachof the streams of a given group will be directed to converge together ata common point. This arrangement results in a net movement of the fluidmaterial from the grid plate at a lower velocity and a greatly reducedkinetic energy. The outlet surface of the distribution plate ispreferably provided with a plurality 0f concave or dished indentations,each accom-odating a group of three of the small holes. Each hole thuspasses through the plate to terminate within a dished indentation whichis formed to provide a surface Vapproximately normal to the axis of eachof the small holes.

One of the principal advantagesy of the im-J proved perforateddistribution plate of this type is the velocity and kinetic energyreducing fea.

lof the Vessel, Yat a point to pass upwardly through the chargestream,vwhile" just above the inlet conduit, thus allowing utilizationof the cone itself for contacting and conversion purposes. Anotherfeature of the distribution plate which is very desirable is the factthat the improved grid may be made much smaller and thereby eliminatemuch of the structural support that is required for the large presenttypes` of grid plates which extend across the whole cross-sectionalAarea of the vessel. A still further advantage lies in the fact that theinlet surface of solid particles to impinge against, it being. providedWith a multiplicity of taperedeach of which will pass a flow streamparticles directly through the plate:

The construction of the distribution grid plate advantageous operatingfeatures more apparent upon reference to the accompanying drawing.

Figure 1 of the drawing shows an elevational view of a portion of alcontact chamber employ- Figure 2 of the drawing shows a' plan view of asmall portion of the improved grid plate as indicated by the line 2-2 inFigure 1.

Figure 3 of the drawing shows a sectional view through. a portionV ofthe grid as indicated by the lines 3 3 in Figure 2.

Referring now to Figure 1 of the drawing, the nunfieralv l designates acylindrically shaped chamber, having a conical bottom head 2. chamberbeing of a type that may be employed for chemical' or catalyticconversion reactions Where small subdivided: solid particles arecontacted by a vaporous or gaseous stream within the chamber. Afluidized stream of particles` is charged to the chamber l by way ofinlet riser or conduit 3, and distributed and diii'used by distributionplate 4 into a turbulent uidized bed within the chamber I. The'fluidized bed resul-ts from the action of the fluidl med-ium passingthrough the improved perforated plate 4. Reaction or conversion productsresulting from the particular chamber shown in Figure l, is placed justabove the inlet line :i Within the lower portion of cone Z. Aspreviously noted, Figure 3 of the drawing shows a sectional- View with aplurality of cone-like depressions 5 which are another tangentially,equidistant one from the other in an equilateral triangular pattern. Thelower surface of the grid plate, or more specically the inlet side ofthe plate is provided with a plurality of indentations or tapered inletopenings 1. These tapered indentations 7 are preferably conical andadjoin one another with tapered inlets 'i As noted in Figure 2, thecircular or conicalrdepressions 6 when adthe plate has no at surfacesforV appears as a plurality of hexagons adjoining one another in.staggered relationship. The advantage of this, as pointed outpreviously, is that the surface is entirely sloping and does not offerany at surfaces to by solid particles in the now stream.

side through depressions 6, which provide surf aces normal tothe axis ofholes 8. Of special streams enterlngvinlets impinge against each effectis aV reduced upward. movement of the mass in a diffused and evenlydistributed manner.

The perforated distribution plate comprising this invention, as has beennoted, is particularly purposes or for distributing iiow streams inother processes.

desired material ating conditions to be encountered.

I claim as my invention:

l. A perforated fluid distribution plate having a plurality of slopedopenings passing thereside of said plate, said indentations on each sidebeing circular in cross-section and adjoining one another tangentiallyso that their centers are ented in groups of three with each one of agroup terminating in asingle outlet indentation.

2. A perforated fluid distribution plate having n inlet side and anoutlet side, a plurality of loped openings passing through said plate, alurality of tapered inlet indentations on said inet side connecting tosaid sloped openings, a pluality of outlet indentations on said outletside, aaid indentations on each of said sides being cir- :ular incross-section and adjoining one another sangentially so that theircenters are equidistant )ne from the other in an equilateral triangularpattern, said plate having three of said inlet indentations for each ofsaid outlet indentations and said sloped openings oriented in groups ofthree terminating in an outlet indentation common to one group.

3. A perforated uid distribution plate having an inlet side and anoutlet side, a plurality of sloped openings passing therethrough, aplurality of tapered inlet indentations on said inlet side connectingwith said openings, a plurality of conically tapered outlet indentationson said outlet side, said plate having three of said inlet indentationsfor each of said outlet indentations, said indentations on each of saidsides being circular in cross-section and adjoining one anothertangentially so that their centers are equidistant one from the other inan equilateral triangular pattern, said sloped openings oriented ingroups of three openings with each opening of one of said in groupsgroups terminating in a common outlet indenta tion and each directed toconverge at a common point beyond said outlet indentation.

4. A perforated fluid distribution plate having an inlet side and anoutlet side, a plurality of sloped openings passing therethrough, aplurality of conically tapered inlets on said inlet side connecting withsaid openings, a plurality of conically tapered outlets on said outletside, said plate having three of said conically tapered inlets for eachof said tapered outlets, said conically tapered inlets and outlets oneach of said sides being circular in cross-section and adjoining oneanother tangentially so that their centers are equidistant one from theother in an equilateral triangular pattern, said sloped openingsoriented of three openings, with each opening of one of said groupsterminating in a common conically tapered outlet and each opening of asaid group directed to converge at a common point beyond said taperedoutlet.

5. A perforated fluid distribution plate as described in claim 4 furthercharacterized in the provision of point-like projections between theadjacent conically tapered inlets.

HU H RODMAN.

No references cited.

